Intel reached a milestone last week that a lot of companies would like to hype - the company has sold 1 billion x86 processors, according to Mercury Research.The company, which was founded in 1968, is celebrating the x86\u2019s 25th anniversary this year.Ten years after the company was founded, Intel introduced the 8086 processor, a 16-bit chip that contained 29,000 transistors and ran at 5 MHz. A version of the 8086, the 8088, shipped in IBM\u2019s original IBM PC in 1982 - it ran at 4.77 MHz. The 8086, which was backward-compatible with Intel\u2019s 8-bit 8080 and 8085, allowed a megabyte of space to be addressed.\u00a0Today\u2019s Pentium 4 processor, by contrast, contains 55 million transistors and operates at 3.06 GHz - that\u2019s 2,115 times more transistors and 600 times as fast as the 8086.Intel says that laying out the first x86 chip was not a trivial matter. The company had no software to assist in laying out the wiring. Designers worked with a light board and erasers, drawing in transistors with a ruler.The 8086 was not simply transition to 16-bitness. It put in place a \u201cpre-fetch\u201d queue, which fetched instructions and queued them for up processing so the processor\u2019s execution unit would have a steady stream of instructions to work with and not have to wait. It was also capable of multiprocessor configurations, allowing the addition of math coprocessors.The 8086 and 8088 spawned the i286 (80286) chip, which used a protected mode to offer protection between concurrently operating software. It also offered the concept of privilege levels, necessary for use in multi-user operating systems.Although protected mode offered benefits, the 80286 was too complex for most operating systems to use them, Intel claims. Thus, the introduction of the i386 (80386), a 32-bit processor that had memory management features and was backward-compatible with DOS, while being enabled for Windows.The i386 was followed by the speeded-up i486 (80486), and by the first Pentium processor, introduced in 1993. The rest is history - an architecture that is still in use today.Intel x86 processors ship in desktop machines, laptops and servers. Mercury estimates that Intel could ship its next billion processors by as early as 2007.Coincidentally, McDonald\u2019s, whose cheeseburgers provide sustenance for many computer programmers, sold 1 billion burgers by the early 1960s. Before 1994 when it introduced the \u2018billions and billions sold\u2019 campaign, the company had flipped more than 100 billion burgers.